Microcontrollers usually comprise a microprocessor, memory, and a plurality of peripheral devices to form a system on a chip that can be applied in a plurality of applications. Generally, very little if no additional hardware is necessary to design a printed circuit board used for controlling a system in which the microcontroller is integrated. However, often a single or multiple inverter, XOR gate or something similar is necessary to condition signals between devices. These are often costly and require significant board space.
For more flexibility U.S. Pat. No. 6,066,961 discloses to couple a microcontroller with a programmable logic device. This solution, however, still requires significant board space. U.S. Pat. No. 6,898,101 discloses a microcontroller including an integrated programmable logic device. The different embodiments disclosed in these reference however, keep the programmable logic device and its input and outputs still separate from the microcontrollers. In case the necessary logic in a system design requires a combined function of programmable logic device and microcontroller, these embodiments still face the same problems stated above. Hence, there exists a need for an improved combination of a microcontroller and a programmable logic device integrated in a single chip.